Refrigerating apparatus



y 12', 1932- c. F. HENNEY 1,867,261

REFRIGERATING APPARATUS .Fil d April 30, 1930 2 Sheets-Sheet l I NVNTORBY v F ATTORNEY July 12, 1932. c. RHENNEY 1,867,261

REFRIGERATING APPARATUS Filed April 30,. 1930 2 Sheets-Sheet 2 IN VENTOR Patented July 12, 1932 UNITED STATES PATENT OFFICE CHARLES F.HENNEY, OE DAYTON, OHIO, ASSIGNOR TO FRIGIDAJIBE CORPORATION, 01 DAYTON,OHIO, A CORPORATION OF DELAWARE REFRIGERATING APPARATUS Applicationfiled April so,

The present invention relates to evaporators for refrigerating apparatusand more particularly to evaporators of the flooded type.

5 One of the objects of the present invention is to generally improverelatively long horizontal evaporators of the flooded type.

Another object is to improve flooded type evaporators in which the ductsare relatively 1 flat. In carrying out this object it is a more specificobject to provide an enlarged portion in the upper'part of the flat ductto provide an enlarged surface of the liquid.

Further objects and advantages of the pres- 15 ent invention will beapparent from the following description, reference being had to theaccompanying drawings, wherein a preferred form of the present inventionis clearly shown. I

In the drawings:

' Fig. 1 is a front view of a refrigerator, the

upperpart being in section showing one form of my improved evaporator.

"Fig. 2 -ijs a fragmentary view partly in section taken on line 22of'Fig. l; r Fig. 3 is a View of the header of the evaporator shownpartly in section, the section being taken on line 3-3 of Fig. 1;

Fig. 4 is a top plan view of the evaporator; Fig. 5 is a sectional viewtaken on line 55 of Fig. 4;

Fig; 6 is an end view of a display type refrigerator cabinet partly insection showing a modified form of evaporator; Fig. 7 is a rear view ofthe display case partly in section, the section being taken on line 7-7of Fig. 6; i

Fig. 8 is a top plan view of the evaporator shown in Fig. 6;

Fig. -9 is a side view of such evaporator, and Fig. 10 is a sectionalview taken on line 1010 of Fig. 9.

For the purpose of illustrating one form of my invention. I have shownan evaporator in combination with a cabinet in which the 1930. SerialNo. 448,583.

cooling chamber is located in the upper part thereof. This cabinet shownat is provided with a chilling chamber or compartment 21 having a dooropening 22 through which the evaporator 24 can be removed.

This 'door opening is closed by a door 25.

The cabinet 20 also includes a food compartment or compartments 26closed by doors 27. A baffle 28 is disposed between these twocompartments for directing air and for catching condensate dripping fromthe evaporator.

In the specific illustration the evaporator is shown as of the floodedtype in which the flow of refrigerant thereto is controlled by thequantity of refrigerant in the evaporator. It comprises a header 30forming a reservoir for liquid refrigerant. Liquid refrigerant isdelivered to the header from compressing mechanism through a coupling 31and is withdrawn from the header through a coupling 32. These couplingsare'carried by a removable head 33. The flow of refrigerant throughheader 30 is controlled by a float 35 which actuatesa needle valve 36for cutting off the flow through the coupling 31 when a predeterminedlevel of liquid refrigerant is attained within the header. The outlet ofthe evaporator is in the form of a tube 37 which connects with thecoupling 32 and is provided with an oil overflow opening 38 for thepurpose of draining the oil from the evaporator in case there is anexcess quantity of metically sealed, while the opposite ends arehermetically joined with the header. In order to increase the heattransfer surface of the tubes I provide a plurality of fins 46 havingkey-hole shaped slots therein to conform to the keyhole contour of theducts. In the preferred embodiment one fin is connected to a pluralityofducts. In addition to providing the increased heat transfer surface ofthe ducts, the fins 46 closely embrace the ducts so as to preventbulging of the lower portions 43 thereof in case of excessive pressurewithin the evaporator. I

The evaporator shown in Figs. 8 and 9 is particularly adaptable torefrigerators in which the cooling compartment is relatively longhorizontally and relatively narrow longitudinally. One of these typesofrefrigerators is shown in Figs. 6 and 7 in the form of a display case50. The upper insulated portion of the displaycase 50 forms a foodstorage compartment 51. and a chilling chamber or compartment 52separated by a baflle 53. The lower portion of this display case forms acompartment 55 in which other parts of the refrigerating apparatus maybe placed or which may be used as a storage chamber. In the specificillustration two evaporators 56 are placed within the chillingcompartment 52. These evaporators are carried by bracket 57 for spacingsame from the floor of the compartment so as to provide a space belowthe evaporator for the flow of air. The upper part of the evaporator isspaced from the top of the compartment for the entrance of air whichflows downwardly over the evaporator. A removable cover 59 is providedfor compartment 52 so as to provide access to and for the removal of theevaporator.

In this modification only two ducts 40 are shown, these ducts areconnected with the end 60 of the header 30. Each fin 46is connected withboth of the ducts.

In refrigerating systems in which a quan tity of oil is retained forrevolving parts, for example, parts of the compressor, some of the oilis delivered with the refrigerant into the evaporator and in the type ofsystem in which the refrigerant used is heavier than the lubricant, theoil will form a blanket within the evaporator. In the specificillustration, S0 is used as a refrigerant and the oil is known as SunisoNo. 1, manufactured by the Sun Oil Company, having a specific gravityvarying between .900.918 at 60 Fahrenheit. The float 35 maintains therefrigerant level substantially at 61, while thelubricating level isindicated at 62. The ducts 40 of Figs. 8 and 9 and the ducts 40 and 41of the evaporator 24 have their lower portions 43 connected with theheader 30 below the surface of liquid refrigerant while the upperportions 44 communicate with the free space above the lubricant level inthe header. Thus a free space 64 is provided throughout the lengthproper operation thereof. Also by this arrangement gas bubbles may fiowin-their natural manner, namely upwardly, and due to constantebullition, a quantity of oil is carried with the gas bubbles into thefree space whence it is delivered through the outlet 37 with therefrigerant to the compressor. By constantly withdrawing a quantity ofoil with the gas only a small layer of oil will collect upon therefrigerant.

One of the improvements in the present invention is the enlargement ofthe upper parts of the ducts 40 and 41 as at 44. If the ducts aremaintained the same width at the upper end as at the lower end 43,capillary oil plugs would be present above the liquid refrigerant. Thenan excessive pressure would be necessary below the oil for breakingsame. In accordance with the present invention, '1 en larged the upperportion of the ducts 40 and 41 beyond the capillary limit or bridge ofthe oil. In the specific example the lower portion has an insidediameter of three eighths of an inch while the upper enlarged portionhas an inside diameter-of three quarters of an inch. By this arrangementI find that gas bubbles will pass more readily through the blanket ofoil and in this manner the efliciency of the evaporator is increasedbecause of the decrease in differential between the back pressure andthe pressure of the refrigerant below the blanket of oil.

.Due to the fact that the refrigerant can pass through the oil morereadily, vaporization within the evaporator is more constant, that is,there is a continuous bubbling through the oiland no explosions, due tosuper-heating of the refrigerant, will occur. In this manner a constantquantity of oil will be carried from the evaporator with the gas andtherefore the blanket of oil is maintained at a minimum. The enlargedportion 44 also provides a relatively large disengaging area for liquidrefrigerant. The velocity within the portion 44 is decreased because ofthe enlargement so that if any liquid refrigerant is forced through theoil with thegas, the velocity is such that the liquid will not be drawninto the header as liquid but is permitted to vaporize or fall back intothe main body of liquid in the ducts.

In addition to the above the upper cylindrical flared portion 44increases the strength of the top of the ducts in order to aid the finsin preventing bulging of the same.

WVhile the form of embodiment of the in vention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. An evapo ator for a mechanical refrigerator comprising, a reservoir,a tall narrow keyhole shape in cross section duct extending horizontallyfrom the reservoir, said reservoir and duct being adapted to contain aquantity of liquid refrigerant and a blanket of oil floating on therefrigerant, means for maintaining a substantially constant level ofliquid refrigerant in said reservoir. the ducthaving its lower portionconnected below the surface of liquid refrigerant and its upper portionwith the free space above the oil in the reservoir, said duct beingflared outwardly at the oil blanket.

2. An evaporator for a mechanical refrigerator comprising, a cylindricalreservoir, a

tall narrow keyhole shape in cross section duct connected with acylindrical side wall of the reservoir and extending horizontally fromsaid reservoir, said reservoir and duct being adapted to contain aquantity of liquid refrigerant and a blanket of oil floating on therefrigerant. means for maintaining a substantially constant level-ofliquid refrigerant in said reservoir. the duct having its lower portionconnected below the surface of liquid refrigerant and its upper portionwith the free space above the oil in the reservoir. said duct beingflared outwardly at the oil blanket.

3. An evaporator for a mechanical refrigerator comprising. a cylindricalreservoir. a plurality of tall narrow keyhole shape in cross sectionducts connected with a cylindrical side wall of the reservoir andextending horizontall from said reservoir, said reservoir and ductsbeing adapted to contain a quantitiy of liquid refrigerantand a blanketof oil floating on the refrigerant, means for maintaining asubstantially constant level of liquid refrigerant in said reservoir,the ducts having their lower portions connected below the surface ofliquid refrigerant and their upper portions with the free space abovethe oil in the reservoir. said ducts being flared outwardly at the oilblanket.

4. An evaporator for a mechanical refrigerator comprising. a cylindricalreservoir. a plurality of tall narrow keyhole shape in cross sectionducts connected with a cylindrical side wall of the reservoir andextending horizontally from said reservoir, said reservoir and ductsbeing adapted to contain a quantitv of liquid refrigerant and a blanketof oil.

floating on the refrigerant. means for maintaining a substantiallyconstant level of liquid refrigerant in said reservoir, the ducts havingtheir lower portions connectcd'belmv the surface of liquid refrigerantand their upper portions with the free space above the oil in thereservoir, said ducts being flared outwardly at the oil blanket, and finmeans thermally connected with said ducts.

5. An evaporator for a mechanical refrigerator comprising, a cylindricalreservoir. a plurality of tall narrow keyhole shape in cross sectionducts connected with a cylindrical side wall of the reservoir andextending horizontally from said reservoir, said reserquantity of liquidrefrigerant and a blanket of oil floating on the refrigerant, means formaintaining a substantially constant level of liquid refrigerant in saidreservoir the duct having its lower portion connected below the liquidrefrigerant level and its upper por- .tion with the free space above theoil level in the reservoir. said duct being flared outwardly at the oilblanket, and a plurality of fin means arranged transversely of the ductsand bridging the space between same.

6. An evaporator for a mechanical refrigerator comprising. a reservoirfor liquid'refrigerant, means for maintaining a substantially constantlevel of liquid refrigerant in said reservoir a plurality of tall narrowkeyhole shape in cross section ducts extending horizontally from thereservoir, one of said ducts being connected to one side of thereservoir and another of said ducts to a different side of saidreservoir, said ducts having a lower portion of an end of each connectedbelow the surface of liquid refrigerant and the upper portions of saidends connected with the free space above the liquid.

7. An evaporator for a mechanical refrigerator comprising, a reservoirfor liquid refrigerant, means for maintaining a substantially constantlevel of liquid refrigerant in said reservoir, a plurality of tallnarrow keyhole shape in cross section ducts extending horizontally fromthe reservoir, one of said ducts being connected to one side of thereservoir and another of said ducts to the opposite side of saidreservoir, said ducts having a lower portion of an end of each connectedbelow .the surface of liquid refrigerant and the upper portions of saidends connected with the free space above the liquid.

8. An evaporator for a mechanical refrigerator comprising, ahorizontally elongated and cylindrical reservoir for liquid refrigerant,means for maintaining a substantially constant level of liquidrefrigerant in said reservoir, a plurality of tall narrow keyhole shapein cross section ducts extending horizontally from one side of thereservoir, similar ducts extendingfrom the opposite side of saidreservoir, said ducts having a lower portion of an end of each connectedbelow the surface of liquid refrigerant and the up per portions of saidends connected with the free space above the liquid.

9. An evaporator for a mechanical refrigerator comprising a reservoir, atall, narrow voir and duct being adapted to contain-a Y duct extendinghorizontally from the reservoir, said reservoir and duct being adaptedto contain a quantity of liquid refrigerant and a blanket of oilfloating on the refrigerant, means for regulating the level of liquidrefrigerant within the reservoir, the cross section of said duct havingthe shape of a keyhole, the narrow lower portion of the duct beingconnected below the surface of the liquid refrigerant and the roundedupper portion being above the surface of liquid refrigerant.

In testimony whereof I hereto aflix my signature.

CHARLE S F. HENNEY.

